Time to evaluate bull performance

The life of a bull is not simple because, for the most part, his life is somewhat confrontational. The other day while reviewing the bulls, two of the bulls still were sparring for dominance. They have been out of the pasture for almost two months, but they still seem to find the energy to spar.

Too often, bulls are penned and the rest of the fall activity goes on, so we forget to check on the bulls. However, the Dickinson Research Extension Center evaluates bulls critically following breeding. Bulls that have a high risk of not passing next spring’s breeding soundness exam are sold.

The science of aging probably would indicate that the old bulls still are sound and good for another year. Unfortunately, oftentimes their attitude changes as well. The probability that a bull may consider a human as just another bull that needs to be put in his or her place is very real.

A bull’s increasing temperament and the fact that a bull easily can add on another 300 pounds each year makes culling bulls a practical decision. The old bulls go to town and yearling bulls that are not holding up their end of the bargain are neutered and sent to the feedlot.

If the truth be told, bull performance, in combination with fall pregnancy checking, is much like the old report card. Bulls that did not perform are accounted for. However, bull effects that are detectable at pregnancy evaluation often are overlooked because many times cows are exposed to more than one bull.

The cows also often are bunched, so the individual mating groups may not be evaluated.

However, when the cows are evaluated, male fertility problems will show up. I can think of one previous example at the center when a single-sire mating group went unnoticed. The bull was not breeding, so nothing was bred. It was a bad day. The excuse was that these cows where in a far pasture, but the lesson learned was to spend more time observing cows.

This year, the center has been pregnancy checking the brood cows as the calves are weaned. The results have been good to excellent. However, there was one group of 41 cows that was not so good. Even prior to weaning, the center already knew that the two yearling bulls were not working well.

One bull had suffered a broken penis. The assumption was that the other bull would cover the cows. That obviously was not a very good scenario during the breeding season, and the center staff was a little nervous about the second bull. Sometimes, that sixth sense is true.

The bulls were turned out on July 31 and the injured bull was pulled on Sept. 3, but a replacement bull was put in the pasture on the same day.

After evaluating the ultrasound results for pregnancy, the two original bulls only conceived seven pregnancies the first 21 days of the breeding season.

During the second 21 days of the breeding season, prior to replacing the injured bull, 13 conceived in 13 days. When the replacement bull was added, 15 cows conceived in eight days.

In total, 28 cows conceived in the second 21 days of the breeding season and three additional cows conceived at the beginning of the third 21 days of the breeding season. Three cows were open, for a total of 41 cows, so the bulls apparently did not do well.

In summary, during the first 21 days of the breeding season, only 17 percent of the exposed cows conceived. During the second 21 days, 68 percent of the exposed cows conceived. Finally, during the third 21 days of the breeding season, 7 percent of the exposed cows conceived.

Obviously this was a reproductive issue that could be a bull or cow problem.

However, when compared with all the other groups that were being evaluated for pregnancy, this particular set of cows obviously was low. The problem was more than likely a bull problem because the bulls were not breeding even before the one bull was injured. Why? Who knows?

The bulls were evaluated and passed their breeding soundness exam. They were phenotypically good bulls and structurally sound. There was no indication that they would have a questionable breeding performance. The bottom line is that, despite all the good science and husbandry, that sixth sense needs to take over sometimes.

In some cases, bulls do not adapt well to the cows or pasture. They may have no natural desire to mate or are just not very sexually aggressive.

Like many things in the beef business, the collection of data is slow and tedious. Many times, as in this case, the data comes in long after the optimum time to do something about the situation. However, it is never too late to review and rethink for next year.

Check the bull pen, read the pregnancy report card and cull those bulls or cows that do not meet your expectations.